A device for three-dimensional registration of human movement

A device for three-dimensional registration of human movement was tested. For this, a special garment with 43 attached light-emitting diodes was developed. The garment was specially designed for biomechanical purposes and made of a highly elastic material in the form of an overall. A recording system working with infra-red light was also tested considering both technical aspects and software. Test recordings of predetermined body movements within a defined work area of over 10m² showed that the device satisfies general practical requirements. The garment worked very well for different movements and for bodies of different shapes and sizes. Technically the system was tested with respect to noise and linearity, operating function, range and manageability. It worked well with some limitations such as reflections. The tested software functions, such as recording speed, processing time, interpolation and user compatibility, proved to fulfil their main needs.     

A virtual fixture using a FE-based transformation model embedded into a constrained optimization for the dimensional inspection of nonrigid parts

Virtually mounting nonrigid parts onto their fixture is proposed by researchers to remove the need for the use of complex physical inspection fixtures during the measurement process. Current approaches necessitate the pre-processing of the free-state nonrigid part’s point cloud into a suitable finite element (FE) mesh and are limited by the use of the boundary conditions setting methods available in FE software. In addition to these limits, these approaches do not take into account the forces used to restrain the part during the inspection, as commonly mandated for aerospace panels. To address these shortcomings, this paper presents a virtual fixture method that predicts the fixed shape of the part without the aforementioned drawbacks of current approaches. This is achieved by embedding information retrieved from a FE analysis of the nominal CAD model into a boundary displacement constrained optimization. To evaluate the proposed method, two case studies on physical parts are performed using the proposed virtual fixture method to evaluate the profile and assembly force specifications of each part.     

一种HDI板对位方式简析

HDI板的对位精度问题主要涉及有通孔、盲孔与外层干膜的对位偏移问题,板边工具孔作为线路板工序生产必须的定位孔,其精度与对位方式决定线路板的生产精度。文章主要介绍一种HDI板的对位方式,重点解决HDI板通孔与盲孔的对位匹配,从而保证外层的孔环无崩孔问题。     

背板加工技术简述

背板作为印制电路板的一种,因其结构特性、应用领域等,挑战常规印制电路板多项加工技术。本文浅谈背板加工流程之压合层间对准度、钻孔背钻、孔金属化深镀能力及最终表面工艺方面的技术及控制项,供同行参考与借鉴。     

An integrated approach of reverse engineering aided remanufacturing process for worn components

The worn mechanical components/parts arrived in the remanufacturing system exhibit highly uncontrolled variabilities in failure conditions as well as structures and shape complexities. With the aid of reverse engineering (RE) technologies, a quick and accurate acquisition of the damaged areas of the worn part is attainable and thereby facilitates remanufacturing operations necessary to bring the parts back to like-new conditions. In this paper, a reverse engineering based approach is proposed to aid the remanufacturing processes of worn parts. The proposed approach integrates 3D surface data collection, nominal model reconstruction, fine registration, extraction of additive/subtractive repair, tool path generation and actual machining process, seeking to improve the reliability and efficiency of manual repair process. For nominal model reconstruction, a Prominent Cross-Section algorithm embedded with curvature constraint is proposed to automatically identify the boundary of the part's damaged area and thereby eliminate the defective point clouds from the reconstruction process. With the nominal reconstruction model and the 3D model of the worn part, a modified ICP algorithm integrating curvature and distance constraints is proposed to achieve a best-fit position of the two models by automatically identifying and eliminating the unreliable corresponding pairs through iterations. The proposed approach is demonstrated through remanufacturing of two different mechanical components and is approved to be efficient and effective.     

专科学院子系统的开发

本文讨论深圳大学管理信息系统中专科学院子系统的开发,阐述其实现原理、方法及有关技术问题。     

送料框架的定位控制

分析了一种纵向、横向平面运行的定位控制方法。     

Does a watched pot boil? A time-series analysis of New York State's sex offender registration and notification law.

Despite the fact that the federal and many state governments have enacted registration and community notification laws as a means to better protect communities from sexual offending, limited empirical research has been conducted to examine the impact of such legislation on public safety. Therefore, utilizing time-series analyses, this study examined differences in sexual offense arrest rates before and after the enactment of New York State's Sex Offender Registration Act. Results provide no support for the effectiveness of registration and community notification laws in reducing sexual offending by: (a) rapists, (b) child molesters, (c) sexual recidivists, or (d) first-time sex offenders. Analyses also showed that over 95% of all sexual offense arrests were committed by first-time sex offenders, casting doubt on the ability of laws that target repeat offenders to meaningfully reduce sexual offending. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PyxosTM技术介绍(新)

Pyxos FT协议是基于时分复用（TDM）的机制。一个Pyxos FT系统由一个Pilot和最多32个Pyxos Points组成。每一个Point分配有一个时间片，用于确定何时允许该Point使用通信介质。Pilot一次向每一个Point发送一个数据包，然后从每一个Point接收一个数据包，然后重复上述过程。这个机制本身避免了竞争和冲撞，数据在给定的时间内可以确定性地交付到目的地。     

Edge registration versus triangular mesh registration, a comparative study

This paper presents a comparative study of two techniques for registering range images. The first one consists in registering range images represented by means of compact adaptive triangular meshes. The second approach registers the same range images but represented by means of their edges. In both approaches the ICP algorithm is used to compute the registration parameters (rotation and translation). The main objective in both approaches is to register a compact representation instead of all original data points. The proposed comparative study is performed in an experimental way by using a set of real range images considering both structured and sculptured objects. Four different criteria are taken into account to perform the comparison: (1) robustness with respect to initial conditions (estimated relative positions between the range images to be registered), (2) robustness with respect to resolutions of set of points on which the ICP method is executed, (3) robustness with respect to overlapping between view fields, and (4) number of iterations versus registration error. By employing these criteria, triangular mesh based and edge based registrations are tested on several range images and results are compared with respect to the ground truth. Conclusions from these experimental results are presented.